


You Had Me at Yellow

by Cupcake_Princess



Series: Our Serendipity [2]
Category: Undertale (Video Game)
Genre: A RETELLING FROM SANS' PERSPECTIVE, Angst and Fluff and Smut, F/F, F/M, M/M, Reader Is Not Chara (Undertale), Reader Is Not Frisk (Undertale), Reader has a vagina, Sans is awkward af, Slow Burn, Speciesism, This will make more sense if you read to ch22 of Catharsis first, no seriously, puns, reader uses she/her pronouns, there's gonna be porn
Language: English
Status: In-Progress
Published: 2018-12-02
Updated: 2018-12-08
Packaged: 2019-09-05 09:42:25
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 3,943
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16808131
Author URL: https://archiveofourown.org/users/Cupcake_Princess/pseuds/Cupcake_Princess
Summary: Why did she glow?Sans still didn't know. He might never figure it out.But she washereand that's what mattered.





	1. A Light in the Dark

**Author's Note:**

> PLEASE READ UP TO CH22 OF CATHARSIS FIRST!!!! I don't know how much sense this is gonna make by itself, but I guess we shall see...  
> Welcome to the shitshow :)

**Notes for the Chapter:**

> This chapter = chapter one of Catharsis

Sans had an odd relationship with the dark. He tolerated it, but barely. Surviving on a knife’s edge, hoping and praying that whatever things lived in it wouldn’t find him again.

But no matter how hard he tried, the dreams never stopped.

And that was how he ended up on this stupid errand of Undyne’s. Night watch, because he couldn’t sleep and needed something to do.

Kicking a discarded cigarette butt into the drain, he sighed. She really hadn’t let up on the sentry duties, even now.

Five years aboveground.

Five years of waiting.

Sans despised the dark. Because every time he found himself in it, it reminded him that things could so easily… stop.

For now, he was content to sit on the low wall near the library and wait. Because somebody was about to have a bad time. Whether it would be an anti-monster protester, or just Undyne for making him scope out the university at this ridiculous hour was still to be seen. No matter what, Sans knew _he_ was already having one.

Bringing his hood up served no real purpose. It wasn’t like he got cold, but hey, at least it made him just look like a chilly student instead of, well, a skeleton.

He’d almost dozed off when a figure strode past. Sans could feel the hate radiating off him without even looking. He did anyway.

LV: 2 HP: 35/35

AT: 10 DF: 10

It was very unusual to see anyone with LV above 1 around here. He’d only seen something like that a few times recently. Well, discounting in his own reflection.

But then again, he’d only seen one other with stats like his, and they shouldn’t exist here.

Turing his idle thoughts back to the shadowy man, Sans noticed he was clutching a wad of paper. Not unusual on campus, but when he paused at the corner to paste a flyer up, what was on it suddenly became top priority.

 _welp. looks like undyne was right._ He really hadn’t wanted to do this tonight. He’d promised to spend it with Papyrus, reminiscing about old times before-

Now really wasn’t the time to think about his brother’s impeding wedding.

Eyes following the culprit into the library, Sans whipped out his phone, dialling the on-campus security.

“yeah, uh, there’s a suspicious guy sticking up anti-monster posters around campus. he’s in the library.” Listening to the operator’s cool tones as she reassured him someone would be over shortly, he zoned out a little.

That was, until he felt a jolt. Something was wrong.

Hanging up, he snuck over to the library entrance. Sans was playing a dangerous game here, and he didn’t know why, but something in that building was calling out to him.

As soon as he opened the door, the gentle pull turned into screaming.

He could hear the shouting before he’d even entered. “Why can’t you women be satisfied with your own _species?_ ” It made his blood run cold. Well, it would if he had any.

There were two people in the elevator. The man he’d been tracking was there, towering above a young woman who lay on the ground, clutching her head.

He’d hurt her. **_he’d hurt her._**

“We’re just trying to fuckin’ protect you, and this is the thanks we get?”

“sure doesn’t look that way.” The words caught in his throat. Giving a warning was the right thing to do. Even if the guy didn’t deserve it.

“Move on,” he ground out, without even turning to face him. _ohhh this guy has no idea who he’s dealin’ with._

Sans had been about to step forwards when the woman called out; a thin, terrified voice that he had to strain to hear. “P-please help.”

That tone. She was begging him to stop as if she didn’t believe he would.

“Shut up.” The man kicked her arm, coming scant inches from her temple. She curled up into a ball, waiting for the next blow to come.

**_as if._ **

Sans should have done this from the start. He knew waiting had only given the attacker another opportunity to hurt her, but it wasn’t like he could skip that step. _you gotta give people a chance… welp, here goes nothin’._

Feeling the familiar burn of his magic rippling out of his eye, Sans smirked. It had been a while since he’d had a chance to stretch.

“What the fuck?”

He could feel the man struggling, trying desperately to break free. _heh. that ain’t happening._

Huh. he hadn’t noticed before. The guy was integrity. Woooooow.

It looked like the woman was just lying there, staring up at the faint blue aura in either amazement or a daze. It was a little concerning.

Aaaand the guy was still screaming. It was giving him a serious headache.

“sorry pal, i don’t just ‘move on’.” Sans said, pushing his way into the elevator to glare up at him. It was worth the extra effort if just to see the look of revulsion on his face when he realised he was being touched by monster magic. “and if i were you, i’d learn from this. otherwise… **y o u ’ r e g o n n a h a v e a r e a l b a d t i m e.** ”

That did it. It was a stupid party trick really, but it seemed humans definitely did not like his serious face. Besides, this time Sans was actually mad enough to use it to full effect.

Turning around, he crouched to help the woman up.

“you alright kid?” Meeting her eyes, he extended a hand…

… and suddenly all he could see was yellow.

LV: 1 HP: 10/20

AT: 15 DF: 9

It totally blindsided him. She was glowing so brightly he had to take a second to realise it was indeed just her soul and not a flashlight or something. Not that anything man-made could produce such a warm light.

_beautiful._

“Beautiful,” she murmured, echoing his thoughts. Her words brought him back down to earth with a sharp thud, reality setting in immediately. The shitstain behind him was screaming again, and the woman on the floor looked more dazed than she should. So, Sans replied in the most sensible way he could.

“nice of ya to say, but i’m all skin and bones really. well, _sans_ the skin. i’m sans, by the way.”

Her brow creased in confusion for a few seconds, and Sans bit back a chuckle. _she’s injured for fuck’s sake._

“___. I really said that out loud, didn’t I?” she eventually said. Her voice was nice now she wasn’t terrified, although Sans had no idea why she suddenly wasn’t. ____ though? nice._ Her face was slowly turning red with embarrassment.

“yup.” She still wasn’t making any move to stand, and frankly it was more than a little concerning. “d’ya need a hand standing up?”

“I… please.”

The moment her hand touched his, Sans knew she wasn’t gonna be able to pull herself up. Using a little more magic, he reached out and slightly altered her gravity. Just a little. She probably wouldn’t even notice. He hoped she didn’t.

 _so uhh, injured humans… she needs to sit down._ Pulling her out into the foyer, he cast a sharp glance at her attacker. The elevator door was shutting again and again on his foot and feeling a need for something… sharper, Sans ever so slightly increased the pressure on him. It was a little vindictive, but frankly he deserved worse.

“Is that you?” The question was a little out of the blue, but he’d been expecting it. Most humans found his magic a weird, although the way she blurted it out was kind of funny.

Sans snorted. “yeah, and frankly he’s lucky i’m just holding him there. don’t want trouble with security when they get here.”

It took a second or two for her to process that information, but eventually she responded. “Do I need to call them?”

 _like i’d make you do that in this state._ Her words were overlapping, almost sounding a little drunk at this point. He carefully pushed her into a chair.

“already taken care of. i saw this lowlife creeping about earlier, sticking posters up. didn’t think anyone would get hurt, so i kept my distance but…” He huffed. “i should not have done that.” There was no way he was going to tell her about the pull he’d felt. Sans wasn’t even sure what that had been himself, and humans tended to get a little weird when souls came up in conversation.

Damnit, every time his thoughts returned to ___’s soul, it very nearly blinded him again. It was way too bright, and even though he could only see its vague shape, something about it was just so…

… unusual.

Ah. Carefully, Sans reached up, tugging an earphone out of her ear. She blinked hard, a look of intense confusion coming over her face.

“I didn’t know that was still in there.” Something was definitely wrong.

 _what did undyne say you do at times like this? fuck, was it the eyes?_ Crouching down, he peered into her eyes.

Fuck indeed. They were so pretty, the golden rays of her soul shining through. Why was it so difficult to turn that off? Sans had never had a problem like this before. Usually he had to think about the person’s soul to even see it, but with ___ it was like he had to concentrate _not_ to.

And now he’d been staring at her for far too long. ___’s face was bright red. Sans wondered if he’d embarrassed her again.

“your pupils are a little dilated, did’ja hit your head at all?”

Again, it took a little while for her to reply. “Y-yeah, I think.”

 _that piece of shit is lucky security are coming. otherwise…_ he cut that thought short. There was no point speculating when ___ was injured and probably in need of medical attention. “alright. as soon as someone gets here, we’re going to getcha some help. you might have a concussion.”

She drifted off into a daze as the two security guards arrived. They apologised as they took the man into custody, saying they would have been quicker if they’d known someone got hurt. Sans just smiled grimly. The pair seemed like decent guys, but a question hung over his head.

_would they have come at all had it been a monster?_

He was almost done explaining when ___ spoke again.

“I can’t have a concussion. I have a paper due.” She sounded genuinely distressed at the prospect, and something about the fact she was more concerned about her paper than a head injury was just so unexpected, Sans laughed.

It was a snap decision. He wanted her to get better, and quick.

“i’ll get her to a doctor,” Sans told the guards before crossing back over to ___. She was staring at him, big, puppy-dog eyes that radiated confusion. “i’m sure this is grounds for an extension,” he murmured. _what am i doing?_ he thought, taking her hand and pulling her up. _this ain’t how you get to know someone._

Despite everything rational telling him no, Sans grinned. “gonna get you some help now anyway. smile, kid. you’re about to meet royalty.”

Toriel was gonna give him hell for this.


	2. Unusual

**Notes for the Chapter:**

> This chapter = chapter 2 of Catharsis

“Whaaa…”

The delayed confusion on ___’s face as they popped into Toriel’s kitchen would have been absolutely hilarious had Sans not suddenly realised what he’d done. _i might have just caused the biggest security risk monsterkind has seen since we let frisk fight the king just because they were nice…_

A light swaying of ___’s hand in his made him realise she was looking a bit worse for wear.

_… and i still haven’t explained anything. stars, i’m an idiot._

“hey, it’s ok.” He tried to get her attention. “ya just teleported for the first time. it can get a bit weird, so try to relax and take things nice and slow.”

She realised he was talking halfway through, turning to gaze at him with uncertainty. “Bu-bu-but we were there, and now we’re not, and…”

_first timers, huh._ “yeah, that’s kinda the point of teleportation.” She still stared like nothing made sense. Spotting a chair tucked under the table, Sans activated his magic to pull it out and gently guided her into it. ___ barely noticed.

He was getting a little worried now. Sure, over the years he’d transported injured monsters around the underground, but he hadn’t really thought over the risks associated with humans. Theoretically, it should be fine, but the look in ___’s eyes was concerning. _eyes. check them._

That opened another can of worms. As Sans moved to tilt her head back, he came to the conclusion it probably wasn’t polite to be so hands on. She was completely out of it, making it impossible to say if there was a problem. This kind of behaviour might come off entirely inappropriate.

But… _stars, those eyes…_ Much the same as before he checked her pupils, trying not to stare at the beautiful colour of her soul. It was a losing battle.

“still a little unfocused.” Sans didn’t really mean to say that aloud, it just slipped out as he started to lose himself in golden light. It was like seeing the sun for the first time again; a peaceful glow he wanted to bask in, reassuring and calm. ___’s cheeks flushed again, tinting her face red.

He knew he should stop. She was probably embarrassed as hell, but the serenity of her soul seemed to say otherwise. Regardless, she had a concussion.

But just a second more wouldn’t hurt…

“Sans, what are you doing here?”

_fuck._

Dropping ___’s face, he turned to see Toriel lounging in the doorway. His back had been to her, so it was almost certain she hadn’t seen anything, but that didn’t stop the guilty expression that crossed his face.

Sans needed to say something. Exactly what, he didn’t know. _how the hell d’you explain this?_

Thankfully, ___ chose that moment to let out a quiet giggle.

“Oh,” Toriel murmured, finally realising he wasn’t alone. Her gaze darted between them, unsure where to begin.

“Y-you brought me to the queen’s house?” ___ sounded absolutely horrified. He might have been a little too vague about that.

“yeah, i, err, coulda called ahead. sorry, old lady.”

After a second or two of incredulous silence, Toriel rolled her eyes, chuckling in disbelief before walking closer. It was so like her to just go with the flow, and Sans vowed to thank her later.

“Hello, my child. I am Toriel, and you are…?” ___ still looked confused as hell as she stuttered out her name, which was to be expected really. The queen was gracious as ever. “It is good to meet you. _Now,_ ” she fixed Sans with an amused glare. “Can you please explain what you are doing in my kitchen at this hour?”

There was no point delaying. “i think she has a concussion.”

Toriel went into mother-mode. Softly tilting ___’s chin back, she frowned. “How did this happen?”

“still dunno myself. i was doing a job for undyne at the university and walked in on some asshole beating the shit out of her.”

“The poor dear… you were right to bring her to me.” Straightening up, she shot Sans a look. “Although that is not like you at all. Why _did_ you bring her here?”

“c’mon tori, you know you’re better than any human doctor…” he said, avoiding the question.

“Mhmm.” She wasn’t convinced. “We’ll talk more about that later. For now, I want to know what Undyne had you doing this time.”

Toriel wasn’t supposed to know. But then again, _he_ shouldn’t either. Human politics were so finicky, not taking into account how monsters dealt with their issues. Sans shrugged. “looks like the bastards at humanity’s defence might be a bit more active than they’ve been letting on.”

“What do you mean?”

Glancing at ___’s dazed expression, he wondered if it was wise to be discussing this in front of her. To be completely honest, she probably wouldn’t understand or remember it which was undoubtedly for the best. “the guy who did this was lv 2.”

“Oh… goodness Sans, if you hadn’t been there…”

“‘m just glad i was.” The unsaid fact that the man had killed to earn that stat hung in the air. It was best ___ didn’t know after all.

“And you’re sure he was a member?”

Sans lifted a shoulder. “he was sticking up posters and ranting about trying to protect human women. pretty sure that makes him one.”

“So why did he attack ___? It sounds awfully… random.” Toriel was right, of course. With no idea as to what had transpired before he’d arrived, Sans was about to say as much when ___ finally piped up.

“I was tearing up that stupid poster in the lift and he caught me.”

Her words took the two monsters completely by surprise. _She… she was helping us?_ The shock must have been evident on Sans’ face, because she blinked hard, stammering over a response. “H-hey, it’s just not fair, y’know? I didn’t wanna leave it up for someone else to have to look at…”

He’d been right. Her soul… such a bright and powerful sense of justice called even now. ___ was truly something, whether she knew it or not.

Toriel snorted, snapping him out of his daze. “You sure know how to pick them, Sans.”

_wait, what?_ “h-hey!” he called out, but she was already gone, retreating down a corridor into the house.

Thankfully, it looked like ___ had wiped herself out and was now dozing in her chair. Sans wondered how much she’d heard.

Toriel knew him too well. She’d seen something was up, and he’d have to answer for that later.

But that was still some time away, and now he had a moment to think about everything, only one word came to mind.

Moving to lean against the fridge, he murmured: “you are so unusual, y’know?”

Sans didn’t think ___ would hear, but she did, cracking her eyes open to glance at him curiously.

“How?”

“ya did something. most people wouldn’t even look at one of us if we were being directly attacked, let alone voluntarily taking down posters like that.”

Surely, she understood that? It wasn’t normal that humans were so unconditionally accepting, let alone kind enough to go out of their way helping monsters. And yet he hadn’t seen a single trace of revulsion on her face. Not even when he’d touched her.

Sans knew he was one of the more unnerving monsters. Toriel was fluffy, Undyne and Alphys so far removed from what humans considered realistic that they didn’t care… even Napstablook didn’t scare people any more. Well, not since his career as a DJ took off.

But as a skeleton… it was very rare that someone would react positively to his appearance.

And ___ had called him beautiful.

_she didn’t mean it. there is no way someone like her would think that._ Dragging himself back to reality, Sans tried to quash the little glimmer of hope that told him she was different. _she’s concussed,_ he thought bitterly. _when she snaps out of it, realises you’re nothing more than a bag of bones, you’ll part ways. s’not like you’re ever gonna see her again-_

“That’s just dumb.” ___ muttered. “I’m sure there’s a ton of people who’d do the same… like, a _skele_ -ton.”

_holy shit._ Vaguely aware of his jaw dropping open, Sans could do nothing but stare.

Then finally, _finally_ the reality of what ___ had just said clicked, and it was the most unexpected, ridiculous, amazing thing he’d heard in a very long time. Stars, he was _laughing._ A real laugh, something bright and vibrant that he’d thought was long buried beneath years of hurt. Her eyes were wide, not comprehending what was so funny about the terrible pun, but Sans didn’t care. He hadn’t realised how much he’d needed that until it’d happened.

Toriel eyed him warily when she returned, monster candy in hand. He tried to steady himself, breathing deeply.

“it… it’s been a _really_ long day, and turns out, the kid’s _pun_ ny.”

The queen chose to ignore him, instead smiling at ___. “Well, I’ll take that as a good sign. From what I can tell, you do have a very mild concussion, but it’s nothing a bit of monster candy and rest won’t fix.” Sans was about to sigh with relief, but she continued, giving him a side-eye. “ _Although_ I don’t know why you assumed she would be safe to teleport with a head injury.”

_shit._ He knew it probably hadn’t been the best idea but was relatively confident things would work out. “done it before,” he lied. Well, it wasn’t entirely a lie, but as to how valid the same injury on a monster would be as a comparison… “think it’s just disorientating, especially for first timers.”

Toriel wasn’t buying it. “Even so…” She pressed a piece of candy into ___’s hand. “Eat it, child. It will help with the pain.” ___ complied, making a variety of odd expressions as the magic took effect, until she looked up, brow creased. Toriel patted her shoulder. “Monster candy can take a while to get used to for those unaccustomed to its… _sweet_ effects.”

Sans grinned as ___ shook her head. Watching humans try monster food was always hilarious. “But it’s just… gone?”

“aaaaand that’s why i brought ya here. human hospitals don’t have this stuff yet, not until we can push out a few scientists to prove how it works. well, ‘qualified’ ones at least.” _ah. foot meet mouth._

At least Toriel was sympathetic, interrupting before she could ask what he’d meant. “___, do you live with anyone?”

It was more than a little disappointing that Sans hadn’t thought to ask that. _they’ll be worried sick. surely, she-_

“No.” _oh._ She didn’t look too happy about it either, almost shuddering as she spoke.

“Hmm… in that case, I would feel much more comfortable if you took the spare room here tonight, so I can keep an eye on your condition. I have only been able to alleviate your pain, but a concussion itself must heal with time.”

___’s reaction was unexpected. “R-really?” she squeaked.

“That is, if you wouldn’t mind-,” Toriel quickly amended, but she was cut off.

“Of course I wouldn’t mind, it’s just… you’re the queen of monsters…” Sans felt like laughing all over again. _like she cares about that._

“It is simply a title, and I assure you there are much more special people in this world.”

His phone decided to pick that moment to go off.

_“Spooky scary skeletons, send shivers down your spine”_

Sans had only set that as his ringtone for a joke and never changed it back, but right now he didn’t regret it one bit. ___ was fighting down a giggle, and he thought about ignoring the call for a brief moment, just to look a little more. Then he decided how damn creepy that sounded and checked the caller ID, sighing as he realised who it was.

“welp, that’s my bro. gotta go before he tears the campus apart lookin’ for me. i’ll come back tomorrow to make sure ya get home ok. see ya tori. kid.”

Popping out of the kitchen, the last thing he saw was ___’s surprised face, suspended in time for a millisecond.

That was before a much angrier, far more skeletal one appeared in view.

“sup, bro?”

**Notes for the Chapter:**

> Well.......what an interesting conversation.........that raises even more questions than answers............


End file.
